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April 14, 2014

Silly Putty Ingredient Could Help Stem Cells Become Motor Neurons

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redOrbit Staff & Wire Reports - Your Universe Online

An ingredient found in Silly Putty could help scientists more efficiently turn human embryonic stem cells into fully functional specialized cells, according to research published online Sunday in the journal Nature Materials.

In the study, researchers from the University of Michigan report how they were able to coax stem cells to turn into working spinal cord cells by growing them on a soft, extremely fine carpet in which the threads were created from polydimethylsiloxane, one component of the popular children’s toy.

According to the authors, the paper is the first to directly link physical signals to human embryonic stem cell differentiation, which is the process by which source cells morph into one of the body’s 200-plus other types of cells that go on to become muscles, bones, nerves or organs.

Furthermore, their research increases the possibility that scientists will be able to uncover a more efficient way to guide differentiation in stem cells, potentially resulting in new treatment options for Alzheimer’s disease, ALS, Huntington’s disease or similar conditions, assistant professor of mechanical engineering Jianping Fu and his colleagues explained in a statement.

“This is extremely exciting,” said Fu. “To realize promising clinical applications of human embryonic stem cells, we need a better culture system that can reliably produce more target cells that function well. Our approach is a big step in that direction, by using synthetic microengineered surfaces to control mechanical environmental signals.”

He and his University of Michigan colleagues designed a specially engineered growth system in which polydimethylsiloxane served as the threads, and they discovered that by varying the height of the posts, they were able to alter the stiffness of the surface upon which the cells were grown.

Shorter posts were more rigid, while the taller ones were softer. On the taller ones, the stem cells that were grown morphed into nerve cells more often and more quickly than they did on the shorter ones. After a period of three weeks and two days, colonies of spinal cord cells that grew on the softer micropost carpets were four times more pure and 10 times larger than those growing on rigid ones, the study authors noted.

Eva Feldman, a professor of neurology at the university, believes that both embryonic and adult-based stem cell therapies have the potential to help patients grow new nerve cells. She studies ALS, a condition also known as Lou Gehrig’s Disease that kills motor neurons in the brain and spinal cord, and is using the technique to create fresh neuron’s from a patient’s own cells.

“Professor Fu and colleagues have developed an innovative method of generating high-yield and high-purity motor neurons from stem cells,” Feldman explained. “For ALS, discoveries like this provide tools for modeling disease in the laboratory and for developing cell-replacement therapies.”

“Fu's findings go deeper than cell counts,” the university added. “The researchers verified that the new motor neurons they obtained on soft micropost carpets showed electrical behaviors comparable to those of neurons in the human body. They also identified a signaling pathway involved in regulating the mechanically sensitive behaviors.”

The specific signaling pathway, or route by which proteins carry chemical signals from the borders of a cell to its interior, that the study authors are analyzing is known as Hippo/YAP. This pathway is also involved in controlling the size of organs, as well as alternately preventing and causing tumors to grow.